*, dd{
    margin: 0;
    padding: 0;
}
.banner{
    height: 600px;
}
.banner1{
    background: url("../images/banner.jpg");
    background-size: cover;
}
.banner2{
    background: url("../images/banner2.jpg");
    background-size: cover;
}
.banner3{
    background: url("../images/banner3.jpg");
    background-size: cover;
}

.card-body p{
    height: 35px;
}
.main{
    background: url("../images/banner4.jpg") center center;
    background-size: cover;
}

.footer .container {
    font-size: 13px;
    font-family: 黑体;
    color: #323232;
}

@media (max-width: 600px) {
    .banner{
        width: 100%;
        height: 240px;
        background-size: cover;
    }
     .bd-example p{
        font-size: 50%;
        text-align: left;
    }
     .bd-example a{
         font-size: 25%;
     }
    .bd-example h5{
        width: 100%;
        text-align: left;
    }
    .footer{
        text-align: center;
    }
}